BEIJING — Chinese authorities on Tuesday reported an attack on security personnel at a checkpoint in the restive far western region of Xinjiang, confirming a days-old report by a U.S.-backed radio service that said five were killed.

The official confirmation came in an article by the local government about public study sessions against terrorism, apparently set up in response to the Friday attack, although the article provided few details on the attack.

In a Sunday report, Radio Free Asia said assailants stabbed two police officers guarding a security checkpoint in a village in Qaraqash county and set fire to a room in which three other officers were sleeping, killing all five.

Village chief Atawulla Qasim told Radio Free Asia that the attackers locked the door from outside and poured gas into the room through a chimney before setting fire to it.

The local government article said militia members manning a checkpoint were killed. A man who answered the call at the local police station said he had no knowledge of the case.

Confirmation of such attacks can be difficult, because authorities often play down attacks targeting symbols of power.